Feroxyhyte is an Fe(III) oxyhydroxide mineral capable of immobilizing large amounts of Sb(V). However, the mechanisms governing the uptake of Sb(V) by feroxyhyte have not been systematically examined and are poorly understood. This study presents the first investigation of Sb(V) uptake by feroxyhyte through both sorption and coprecipitation processes across an environmentally-relevant range of Sb(V) loadings. Antimony K-edge extended X-ray absorption fine structure (EXAFS) spectroscopy revealed that Sb(V) sorption and coprecipitation (at all loadings) involved the development of edge and corner sharing linkages between SbV(O,OH)6 and multiple FeIII(O,OH)6 octahedra. The Sb K-edge EXAFS results indicate that Sb(V) coprecipitation involved incorporation into feroxyhyte’s structure via heterovalent Sb(V)-for-Fe(III) substitution, while Sb(V) sorption likely involved occupancy of vacant octahedral sites in feroxyhyte’s near-surface structure. As a result of these uptake mechanisms, both sorbed and coprecipitated Sb(V) displayed very strong resistance to desorption via ligand exchange when exposed to SO4 2-- or PO4 3--rich solutions (during a commonly-used sequential extraction scheme). Overall, these findings provide new insights into Sb(V) uptake by feroxyhyte and highlight the role that feroxyhyte can potentially play in treating Sb(V)-contaminated water or stabilizing Sb(V) in contaminated soil, sediment and geogenic waste.
Details
Title
Antimony(V) uptake by feroxyhyte (δ'-FeOOH): Insights from X-ray absorption spectroscopy and selective extractions
Creators
Mona Hosseinpour Moghaddam - Southern Cross University
Niloofar Karimian - Monash University
Scott G Johnston - Southern Cross University
Girish Choppala - University of Newcastle
Mohammad Rastegari - Southern Cross University
Edward D Burton - Southern Cross University
Publication Details
Journal of hazardous materials, Vol.499, pp.1-10
Publisher
Elsevier B.V.
Grant note
This research was supported by the Australian Research Council under Project FT200100449, with supplementary funding provided by Southern Cross University.